Of all the microorganisms known to man, there are few as important as yeast. You may think you are familiar with this organism, but there is still more to know about this organism if you look at it under a microscope.
Yeasts occur in different forms and structures, and identifying them is crucial to deciding what purpose they would serve. And that’s only one of the reasons you need to know what yeast looks like under a microscope. So, what does yeast look like under a microscope? You’ll find out more as you read on.
What is Yeast?
According to Wikipedia, the word ‘yeast’ originates from an Old English word gyst and the Indo-European root yes, which implies boil, foam, or bubble. Records from millenniums of history show that the early world was familiar with this organism and some of its applications.
Yeasts are eukaryotic organisms found under the fungus family. Each yeast is consists of a single cell. There are about 1000 known species of yeast. Moreover, you can find them anywhere in the world and on anything.
Baker’s yeast (Saccharomyces cerevisiae), which people commonly refer to as yeast, is only one of the numerous types available. It also happens to be the most celebrated for its association with man owing to its variable application.
How to view yeast under a microscope
Yeasts are one of the smallest eukaryotic cells, and their size varies between 2 to 10μm diameter. With a size that small, you can’t view them any type of microscope.
Generally, we use a light microscope to view yeast cells. There are two microscopy methods of viewing yeast. The first is the bright field method, while the second is the fluorescent method.
1. Brightfield Method of Viewing
The brightfield method of microscopy involves using a microscope that illuminates the specimen and transmits the reflection to the objective lens.
The brightfield method allows you to see the round or oval shape of the yeast cell units, such as inside the protoplasm. Again, you will be able to see some cellular processes, such as the budding of the new yeast cell. Asides from these things, you won’t be able to see anything else using this method.
You will require a microscope with a magnification of at least 200x. You’ll achieve a better viewing at 400x.
To observe yeast under a brightfield microscope, you will need to place a diluted mix on a slide. Put a coverslip on it, and you are ready to view it under a microscope. Try as many magnifications as you wish. It would only be visible between 200x and 400x.
2. Fluorescent Method of Viewing
This method is the only way to see the intracellular distribution of yeast. The fluorescent microscopy technique involves using a very high magnification compound light microscope with magnification of 1000x and above, and cellular staining.
The purpose of staining is that the yeast, like most microorganisms, is either fully transparent or completely opaque. Using certain dye and staining techniques helps to highlight the parts that are not visible.
With this method, you can identify every other internal part of the yeast cell like the vacuoles, mitochondria, Golgi bodies, and many more.
To observe yeast under the fluorescence method, prepare a wet sample on the slide and place your coverslip. At one side of the coverslip, introduce a drop of dye while placing a paper towel at the opposite end. The paper towel draws the ink under the coverslip and completely covers the specimen. Remove the paper towel and begin your viewing.
Under the fluorescence method, you would see the yeast cell and all organelles mapped out by the ink. For example, the darkest blue portion of the imagery will be the nucleus.
What Type of Microscopes Can See Yeast Cells
Just to be clear, you cannot see yeast cells with naked eyes. There is a reason that they are called microorganisms. The human eyes can only see objects with a width of 0.04mm, which is comparable to fine human hair.
Although microscopes are for magnification, not all microscopes can see a yeast cell. Yeast cells fall between 2 to 10μm in diameter, and that means any microscope that would view it must be powerful enough to do so.
Simple microscope and stereomicroscopes lack the magnification to see yeast cells either in part or whole. The compound light microscope is the choice device for such viewing. Compound microscope magnification varies from 40x to 1000x.
Choosing which to use should be guided by knowing the size of the yeast. A 40x magnification can only see 5mm, which is way bigger than a yeast cell. It follows that 100x will see 2mm and 400x will see 0.45mm 0r 450 microns. Viewing a substance of 0.1180mm size is possible with 1000x magnification.
Microscopes of 200x and higher will see a yeast cell. The level of view and detail you will observe will increase with the magnification power of the microscope.
What does it look like under a microscope?
Yeasts appear in varying forms and shapes. Most of them measure about 0.003 inches in diameter. You may see them occurring independently, in pairs, chains, and clusters.
In terms of structure, research shows that yeasts take different shapes based on their external limitations. As a result, you can find yeast having a form such as spherical, globose, and ellipsoidal under a microscope. Other patterns you could see include cylindrical, apiculate, and ogival.
Also, yeast is immobile. That said! You aren’t expected to see flagella, cilia, or other organs for movement.
Difference between yeasts and other Microorganism under Microscope
While simple experiments such as fermentation can prove the presence of yeasts, you must be able to identify between yeast and other microscopic organisms when viewing under a microscope.
1. Yeast and Fungi
Yeast is a fungus but differs in several ways from other fungi. First, yeast stands as the only unicellular fungi. Others are multicellular, and that affects their behavior. The choice places for finding fungi are damp and dark areas, whereas yeasts can be situated anywhere.
Moreover, most yeast is oval and colorless compared to fungi which are fuzzy and can be of any coloration between red, green, brown, black, and pink.
2. Yeast and Molds
There are several ways to differentiate between yeast cells and mold when viewing under a microscope. First, yeasts consist of individual cells, while molds occur in filaments, also known as hyphae.
Another way of knowing is that when stained, yeast appears either transparent or white, but molds are colorful under a microscope.
Identifying them by the number of cells they possess is also a perfect way to compare. As expected, you will see only a cell for yeast, but molds are multicellular.
3. Yeast and Bacterium
Yeasts and bacteria hold similarities by being unicellular and undergoing anaerobic respiration. However, they are more different than alike in structure. So, when viewing them under a microscope, you should note that bacteria are always smaller than yeast cells.
If you don’t have a magnification of 1000x and above, you won’t see bacteria. So, when you start to see a microorganism between 200x and 400x, you are not seeing bacteria but yeast cells.
Again, while yeast has a nucleus in each cell, bacteria do not possess any nucleus. Hence, if what you see under very high magnification has a nucleus, know that it isn’t bacteria. That should give you an idea of what you see under a microscope.
We can also compare the composition of the cell wall of these organisms. That of yeasts is made of chitin while bacteria’s cell wall is made of murein.
Also, you can easily observe that yeast cells have no organ of movement, but bacteria possess flagella. These are all visible differences you would spot from viewing under a microscope.
What are the uses of Yeast?
Yeasts are very important to man. We’ll attempt to highlight a few of its benefits.
1. Nutrition
Almost everyone has been a beneficiary of yeast action. If you’ve taken a loaf of bread, donuts, yogurt, and much more, yeast was present as a rising agent. Medical practitioners encourage the eating of yeast-rich foods to derive proteins and vitamins. The yeast favored for nutritional purposes is the Saccharomyces cerevisiae, commonly referred to as the baking yeast.
2. Biofuel
As the world tends towards going green, biofuel is receiving more attention. Yeast turns sugar into ethanol, and that knowledge has proven valuable in providing alternatives to diesel. Hence, yeast is now an industrial material for making ethanol.
3. Breweries
This is one of the industries that would ever remain grateful for the discovery of yeasts. Every beer and the likes of it rely on yeast for fermentation.
4. Scientific Research
Yeasts remain of the most researched organisms on earth, and the reasons for this are not far-fetched. First, they are similar to human cells but reproduce much faster.
Again, unlike most organisms, yeasts are relatively safer for experiments. The fact that we already know so much about them gives us an edge when using them. Besides, they are flexible and easy to use for testing drugs rather than more developed organisms.
5. Medical Application
Yeasts or products from it have helped make products to solve diverse health problems. Probiotics and several other drugs have yeasts as one of their supplements.
6. Cosmetology
Cosmetologists have been exploiting proteins and vitamins available in yeast to make products such as nail strengtheners, body creams, and much more. Many skincare products with protein and vitamins have yeast as part of their formula.
Negative Importance of Yeasts
While we would bask in the euphoria of the several benefits of yeast, it is necessary to state that not all yeasts are beneficial to man. Yeasts also have their disadvantages, as we would see in a moment.
1. Health threats
Yeasts can pose some serious threat to our health. Below are some yeasts that can be hazardous to us.
The genus Cryptococcus:
An example is the C. neoformans, commonly found in a bird’s excreta. It becomes a pathogen to a man if inhaled. The pathogen attacks the brain and lungs, and the effects can be life-threatening.
For people with compromised immune systems, the infection can be lethal. The yeast surrounds itself with an unyielding polysaccharide. Consequently, the white blood cells of the host are powerless against it.
Candida albicans:
The yeast naturally occurs in man as part of the flora. Its preferred locations are the gastrointestinal tract, mouth, and vaginal.
There is medical proof that this seemingly harmless yeast can becomes a pathogen to your body. This occurs once the yeast is present more than required. Some problems this yeast variance can cause include oral thrush, fatigue, and recurring genital infections, to mention a few.
Malasseziaglobosa
The yeast naturally occurs on the skin but becomes disadvantageous once its density increases. If you’ve had to deal with dandruff before, then you won’t need much introduction to this yeast.
This dimorphic yeast is also, most often than not, the culprit behind the tinea versicolor, a surface skin infection. You won’t find another organism except this yeast to be responsible for seborrhoeic dermatitis.
2. Food spoilage
There will be but only a few people who haven’t had to experience the action of the yeast of the genus Zygosaccharomyces, notorious for food spoilage.
These yeasts thrive on foods with low pH and high sucrose and organic acid to undergo some processes. As the yeast grows, it changes parts of the food component physically and chemically. Foul odor emits, and the coloration shows you the food isn’t yours to eat anymore.
Meanwhile, when wines get spoilt, Brettanomycesbruxellensis is the yeast to blame.
What causes the increase of yeast in the human body?
When naturally occurring yeasts in our body grow beyond the appropriate measure, they begin to act adversely. Some food and drugs that we take facilitate the growth of yeast in the body. Generally, foods high in sugar content provide the much-needed element for yeasts’ survival. And when there is a continuous supply of these foods in abundance, the yeast population can swell beyond control.
Besides, frequently taking antibiotics and some oral birth control pills have a growth-boosting effect on yeast in the body. Also, should your immune system become weak, yeasts would grow in excess and cause various infections.
Final thoughts
Yeast proves to be highly valuable to humans, and knowing more about them allows us to harness their benefits. It follows that there is no way to know about them other than examining them under a microscope.
But there are many things you can see once you look into the eyepiece. That’s another reason we must answer the question, what does yeast look like under a microscope? Through a comparison of yeast and other similar organisms, we can identify yeast in any sample. By matching, this article dispels reasons to misidentify a yeast cell from others with similar properties.
In addendum, the level of detail you would see of yeast highly depends on the sophistication of the microscope that you use.